The 25-year-old is now four months pregnant and due to give birth at the start of next year. Throughout the evening, she was seen tenderly putting her hand over her expanding tummy.

Mum-to-be Lily was at the event to show support for her own mother, Alison Owen.

She produced the comedy, which stars Gemma Arterton and Mamma Mia's Dominic Cooper and which tells the story of a young journalist who returns to her hometown to discover her childhood house is being put up for sale.

The movie also includes Lily's music – which, according to the star, is all thanks to a bit of family favouritism.

"I mean my mum produced it," she quipped at the premiere. "I think it was a bit of nepotism going on."